<html>
<head>
  <style type="text/css">
    .content {
      padding: 10;
      display: grid;
      grid-template-columns: auto auto auto auto;
      grid-template-rows: auto auto auto;
      height: 780px;   //padding 有个20的宽度
      background-color: #000;
      grid-gap: 10px;
    }
    .b {
      background-color: blue;
    }
  </style>
</head>
<body>
  <div class="content">
    <div class="b">1</div>
    <div class="b">2</div>
    <div class="b">3</div>
    <div class="b">4</div>
    <div class="b">5</div>
    <div class="b">6</div>
    <div class="b">7</div>
    <div class="b">8</div>
    <div class="b">9</div>
  </div>
</body>
</html>
